This invention relates to ferroelectric thin film processes, ferroelectric memory device structures and integrated processes for ferroelectric non-volatile memory devices, and specifically to a method of forming a c-axis oriented PGO thin film on a high-k oxide.
Metal, ferroelectric, insulator, and silicon (MFIS) transistor ferroelectric memory devices have been proposed, and c-axis oriented Pb5Ge3O11 (PGO) thin films exhibit good ferroelectric and electrical properties for one transistor (1T) memory device applications. Extremely high c-axis oriented PGO thin films can be deposited on high-k gate oxides, and working 1T-memory devices with PGO MFIS memory cells have been fabricated. However, the integration process induces damage, such as etching damage, reduces properties of ferroelectric RAM (FRAM) devices, and results in high surface roughness making alignment difficult. In order to resolve these problems, selective deposition processes have been developed to simplify integration processes and improve the properties of MFIS transistor ferroelectric memory devices.
The formation of seed layers for MOCVD of ferroelectric films is described in U. S. patent application Ser. No. 10/020,868, filed May 8, 2001, by Li et al., for Seed layer processes for MOCVD ferroelectric thin films deposited on high-k gate oxides. 
A method of forming a PGO thin film on a high-k dielectric includes preparing a silicon substrate, including forming a high-k gate oxide layer thereon; patterning the high-k gate oxide; annealing the substrate in a first annealing step; placing the substrate in a MOCVD chamber; depositing a PGO thin film by injecting a PGO precursor into the MOCVD chamber; and annealing the structure having a PGO thin film on a high-k gate oxide in a second annealing step.
It is an object of the invention to provide a selective deposition method for c-axis PGO thin films on high-k gate oxides, including ZrOX (X=0-2), HfOX (X=0-2), TiO2, Al2O3, La2O3, and mixtures thereof.
Another object of the invention is to provide for a simplified integration process for c-axis PGO thin films.
A further object of the invention is to provide a PGO MFIS transistor having improved electrical characteristics.
This summary and objectives of the invention are provided to enable quick comprehension of the nature of the invention. A more thorough understanding of the invention may be obtained by reference to the following detailed description of the preferred embodiment of the invention in connection with the drawings.